Recipe: how to cook a best in class 2-ch pre-amp with a/d convertor?

[5thString]

Just to let you know.... I emailed Five Fish Studios today to ask about the usability of their PSU in Europe, and this is the answer:
"The power transformers work with European voltages. The
transformer primary windings can be wired in series (for 220V) or in
parallel for 110V operation."

I think that should answer some questions here.

[john_fromAustria]

How about using an old personal computer power supply? I think that should work? It's capabel of multiple power outputs. Maximum 12v tough, but I think this still should work?

Can anyone tell me if that could work?

[thermos]

Sorry if you've seen this, but I'm selling a racked up/ready to roll one in the classifieds.

[R'shonn]

Hey anybody know what to make of this? (from the classified section) are they saying that you can't use the a/d converters in the pcm4222evm unless you use a special master clock, and that the 4222 is only good for working as a master clock for improving an external a/d interface? for ex: If I used the 4222 out to spdif > aroura lynx card, does that mean that the 4222 is just clocking the lynx card, and that the a/d is still being done by the chipset on the lynx?

somebody give insight, I orderd mine at the begining of the month an still havent got it (backordered)

Originally Posted by Rochey

that clock input is not for wordclock.
It's for masterclock.22.5792MHz ±50ppm (or 24MHz)

Good luck generating that .

/Rochey

Originally Posted by thermos

Wow, really? Are you sure? I best be doing some reading.


Edit: here is what the literature says.

"An external clock source (EXT CLOCK), may be input at BNC connector J11 and is buffered by U19. The
buffer includes a tri-state output, so that it may be disabled when one of the crystal oscillators is used as
the master clock source. Buffer U19 is always operated from the +3.3V supply generated by voltage
regulator U22, and is tolerant to +5V input logic levels. The maximum external master clock frequency is
27.648MHz."

Also, heres the pdf if you feel like reading more.
http://focus.ti.com/lit/ug/sbau124/sbau124.pdf

Originally Posted by Rochey

so in other words, your racked version of the PCM4222 EVM can only be used as the clock master in the system. You'll also have to pin out the word clock the device creates.

Good luck.

/Rochey

[5thString]

Originally Posted by R'shonn

Hey anybody know what to make of this? (from the classified section) are they saying that you can't use the a/d converters in the pcm4222evm unless you use a special master clock, and that the 4222 is only good for working as a master clock for improving an external a/d interface? for ex: If I used the 4222 out to spdif > aroura lynx card, does that mean that the 4222 is just clocking the lynx card, and that the a/d is still being done by the chipset on the lynx?

somebody give insight, I orderd mine at the begining of the month an still havent got it (backordered)

Absolutely not! From what I understand, this discussion only points out the fact that the external clock connector on the 4222evm can only be used to output a masterclock, not to use an external clock to drive the 4222.

But the 4222 is indeed an AD converter in itself!

[Rochey]

The PCM4222's evm has 3 different clock sources.

- 24.567 MHz Crystal
- 22.5792 MHz Crystal
- EXternal Clock. (at similar frequencies)

This makes the EVM (in it's default setting) act as the clock master.

The Data (including the self generated clocks) will come out of the pcm4222 and then into the DIT4192 S/PDIF generator which will then transmit AES data out.

Depending on the interface to the PC that you're feeding this device into, the interface may have to synchronise itself to the incoming S/PDIF.

However, if your product (like the lynx, or the digi192 digital I/O box) has a sample rate converter, then you needn't worry about it.

Running an ADC from it's own clock source, and allowing it to be the clock master will allow it to perform at it's best.

thanks again

Rochey.

P.S - if you DO want to make the PCM4222 a slave, then you'll need an external PLL to create the higher clocks, and drive the EVM appropriately.

Again - The PCM4222 is an awsome ADC, however, it's EVM was never designed to be used as an end product.

[5thString]

Hey guys.

Now I have another question, maybe slightly off-topic but related anyway. What if I want to build a complete ADA box using the PCM42222? I mean, I can use the PCM42222EVM for the AD part allright. What about the DA side? Do you know of a best-in-class DA board, maybe in EVM format as well, that could complete the setup?